1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature sensor
4 *
5 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
6 *
7 * (7-bit I2C slave address 0x60)
8 *
9 * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
10 * interrupts, user offset correction, raw mode
11 */
12
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/iio/iio.h>
16 #include <linux/iio/sysfs.h>
17 #include <linux/iio/trigger_consumer.h>
18 #include <linux/iio/buffer.h>
19 #include <linux/iio/triggered_buffer.h>
20 #include <linux/delay.h>
21
22 #define MPL3115_STATUS 0x00
23 #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
24 #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
25 #define MPL3115_WHO_AM_I 0x0c
26 #define MPL3115_CTRL_REG1 0x26
27
28 #define MPL3115_DEVICE_ID 0xc4
29
30 #define MPL3115_STATUS_PRESS_RDY BIT(2)
31 #define MPL3115_STATUS_TEMP_RDY BIT(1)
32
33 #define MPL3115_CTRL_RESET BIT(2) /* software reset */
34 #define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
35 #define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
36 #define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
37
38 struct mpl3115_data {
39 struct i2c_client *client;
40 struct mutex lock;
41 u8 ctrl_reg1;
42 };
43
mpl3115_request(struct mpl3115_data * data)44 static int mpl3115_request(struct mpl3115_data *data)
45 {
46 int ret, tries = 15;
47
48 /* trigger measurement */
49 ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
50 data->ctrl_reg1 | MPL3115_CTRL_OST);
51 if (ret < 0)
52 return ret;
53
54 while (tries-- > 0) {
55 ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1);
56 if (ret < 0)
57 return ret;
58 /* wait for data ready, i.e. OST cleared */
59 if (!(ret & MPL3115_CTRL_OST))
60 break;
61 msleep(20);
62 }
63
64 if (tries < 0) {
65 dev_err(&data->client->dev, "data not ready\n");
66 return -EIO;
67 }
68
69 return 0;
70 }
71
mpl3115_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)72 static int mpl3115_read_raw(struct iio_dev *indio_dev,
73 struct iio_chan_spec const *chan,
74 int *val, int *val2, long mask)
75 {
76 struct mpl3115_data *data = iio_priv(indio_dev);
77 int ret;
78
79 switch (mask) {
80 case IIO_CHAN_INFO_RAW:
81 ret = iio_device_claim_direct_mode(indio_dev);
82 if (ret)
83 return ret;
84
85 switch (chan->type) {
86 case IIO_PRESSURE: { /* in 0.25 pascal / LSB */
87 __be32 tmp = 0;
88
89 mutex_lock(&data->lock);
90 ret = mpl3115_request(data);
91 if (ret < 0) {
92 mutex_unlock(&data->lock);
93 break;
94 }
95 ret = i2c_smbus_read_i2c_block_data(data->client,
96 MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
97 mutex_unlock(&data->lock);
98 if (ret < 0)
99 break;
100 *val = be32_to_cpu(tmp) >> chan->scan_type.shift;
101 ret = IIO_VAL_INT;
102 break;
103 }
104 case IIO_TEMP: { /* in 0.0625 celsius / LSB */
105 __be16 tmp;
106
107 mutex_lock(&data->lock);
108 ret = mpl3115_request(data);
109 if (ret < 0) {
110 mutex_unlock(&data->lock);
111 break;
112 }
113 ret = i2c_smbus_read_i2c_block_data(data->client,
114 MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
115 mutex_unlock(&data->lock);
116 if (ret < 0)
117 break;
118 *val = sign_extend32(be16_to_cpu(tmp) >> chan->scan_type.shift,
119 chan->scan_type.realbits - 1);
120 ret = IIO_VAL_INT;
121 break;
122 }
123 default:
124 ret = -EINVAL;
125 break;
126 }
127
128 iio_device_release_direct_mode(indio_dev);
129 return ret;
130
131 case IIO_CHAN_INFO_SCALE:
132 switch (chan->type) {
133 case IIO_PRESSURE:
134 *val = 0;
135 *val2 = 250; /* want kilopascal */
136 return IIO_VAL_INT_PLUS_MICRO;
137 case IIO_TEMP:
138 *val = 0;
139 *val2 = 62500;
140 return IIO_VAL_INT_PLUS_MICRO;
141 default:
142 return -EINVAL;
143 }
144 }
145 return -EINVAL;
146 }
147
mpl3115_trigger_handler(int irq,void * p)148 static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
149 {
150 struct iio_poll_func *pf = p;
151 struct iio_dev *indio_dev = pf->indio_dev;
152 struct mpl3115_data *data = iio_priv(indio_dev);
153 /*
154 * 32-bit channel + 16-bit channel + padding + ts
155 * Note that it is possible for only one of the first 2
156 * channels to be enabled. If that happens, the first element
157 * of the buffer may be either 16 or 32-bits. As such we cannot
158 * use a simple structure definition to express this data layout.
159 */
160 u8 buffer[16] __aligned(8);
161 int ret, pos = 0;
162
163 mutex_lock(&data->lock);
164 ret = mpl3115_request(data);
165 if (ret < 0) {
166 mutex_unlock(&data->lock);
167 goto done;
168 }
169
170 memset(buffer, 0, sizeof(buffer));
171 if (test_bit(0, indio_dev->active_scan_mask)) {
172 ret = i2c_smbus_read_i2c_block_data(data->client,
173 MPL3115_OUT_PRESS, 3, &buffer[pos]);
174 if (ret < 0) {
175 mutex_unlock(&data->lock);
176 goto done;
177 }
178 pos += 4;
179 }
180
181 if (test_bit(1, indio_dev->active_scan_mask)) {
182 ret = i2c_smbus_read_i2c_block_data(data->client,
183 MPL3115_OUT_TEMP, 2, &buffer[pos]);
184 if (ret < 0) {
185 mutex_unlock(&data->lock);
186 goto done;
187 }
188 }
189 mutex_unlock(&data->lock);
190
191 iio_push_to_buffers_with_timestamp(indio_dev, buffer,
192 iio_get_time_ns(indio_dev));
193
194 done:
195 iio_trigger_notify_done(indio_dev->trig);
196 return IRQ_HANDLED;
197 }
198
199 static const struct iio_chan_spec mpl3115_channels[] = {
200 {
201 .type = IIO_PRESSURE,
202 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
203 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
204 .scan_index = 0,
205 .scan_type = {
206 .sign = 'u',
207 .realbits = 20,
208 .storagebits = 32,
209 .shift = 12,
210 .endianness = IIO_BE,
211 }
212 },
213 {
214 .type = IIO_TEMP,
215 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
216 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
217 .scan_index = 1,
218 .scan_type = {
219 .sign = 's',
220 .realbits = 12,
221 .storagebits = 16,
222 .shift = 4,
223 .endianness = IIO_BE,
224 }
225 },
226 IIO_CHAN_SOFT_TIMESTAMP(2),
227 };
228
229 static const struct iio_info mpl3115_info = {
230 .read_raw = &mpl3115_read_raw,
231 };
232
mpl3115_probe(struct i2c_client * client)233 static int mpl3115_probe(struct i2c_client *client)
234 {
235 const struct i2c_device_id *id = i2c_client_get_device_id(client);
236 struct mpl3115_data *data;
237 struct iio_dev *indio_dev;
238 int ret;
239
240 ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
241 if (ret < 0)
242 return ret;
243 if (ret != MPL3115_DEVICE_ID)
244 return -ENODEV;
245
246 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
247 if (!indio_dev)
248 return -ENOMEM;
249
250 data = iio_priv(indio_dev);
251 data->client = client;
252 mutex_init(&data->lock);
253
254 i2c_set_clientdata(client, indio_dev);
255 indio_dev->info = &mpl3115_info;
256 indio_dev->name = id->name;
257 indio_dev->modes = INDIO_DIRECT_MODE;
258 indio_dev->channels = mpl3115_channels;
259 indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
260
261 /* software reset, I2C transfer is aborted (fails) */
262 i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
263 MPL3115_CTRL_RESET);
264 msleep(50);
265
266 data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
267 ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
268 data->ctrl_reg1);
269 if (ret < 0)
270 return ret;
271
272 ret = iio_triggered_buffer_setup(indio_dev, NULL,
273 mpl3115_trigger_handler, NULL);
274 if (ret < 0)
275 return ret;
276
277 ret = iio_device_register(indio_dev);
278 if (ret < 0)
279 goto buffer_cleanup;
280 return 0;
281
282 buffer_cleanup:
283 iio_triggered_buffer_cleanup(indio_dev);
284 return ret;
285 }
286
mpl3115_standby(struct mpl3115_data * data)287 static int mpl3115_standby(struct mpl3115_data *data)
288 {
289 return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
290 data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
291 }
292
mpl3115_remove(struct i2c_client * client)293 static void mpl3115_remove(struct i2c_client *client)
294 {
295 struct iio_dev *indio_dev = i2c_get_clientdata(client);
296
297 iio_device_unregister(indio_dev);
298 iio_triggered_buffer_cleanup(indio_dev);
299 mpl3115_standby(iio_priv(indio_dev));
300 }
301
mpl3115_suspend(struct device * dev)302 static int mpl3115_suspend(struct device *dev)
303 {
304 return mpl3115_standby(iio_priv(i2c_get_clientdata(
305 to_i2c_client(dev))));
306 }
307
mpl3115_resume(struct device * dev)308 static int mpl3115_resume(struct device *dev)
309 {
310 struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
311 to_i2c_client(dev)));
312
313 return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
314 data->ctrl_reg1);
315 }
316
317 static DEFINE_SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend,
318 mpl3115_resume);
319
320 static const struct i2c_device_id mpl3115_id[] = {
321 { "mpl3115", 0 },
322 { }
323 };
324 MODULE_DEVICE_TABLE(i2c, mpl3115_id);
325
326 static const struct of_device_id mpl3115_of_match[] = {
327 { .compatible = "fsl,mpl3115" },
328 { }
329 };
330 MODULE_DEVICE_TABLE(of, mpl3115_of_match);
331
332 static struct i2c_driver mpl3115_driver = {
333 .driver = {
334 .name = "mpl3115",
335 .of_match_table = mpl3115_of_match,
336 .pm = pm_sleep_ptr(&mpl3115_pm_ops),
337 },
338 .probe = mpl3115_probe,
339 .remove = mpl3115_remove,
340 .id_table = mpl3115_id,
341 };
342 module_i2c_driver(mpl3115_driver);
343
344 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
345 MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
346 MODULE_LICENSE("GPL");
347
